Oligomers with di-phenylethynyl endcaps

ABSTRACT

An oligomer having di-phenylethynyl endcaps is disclosed. The capped oligomer has the formula:
 
D-A-D
 
     wherein 
     D is a di-phenylethynyl endcap; and 
     A is an oligomer selected from the group consisting of imidesulfone; ether; ethersulfone; amide; imide; ester; estersulfone; etherimide; amideimide; oxazole; oxazole sulfone; thiazole; thiazole sulfone; imidazole; and imidazole sulfone.

BACKGROUND OF THE DISCLOSURE

The present disclosure relates generally to difunctional end-cappedoligomers, and more particularly to oligomers with di-phenylethynylendcaps.

Only a few of the thermosetting resins that are commonly used today infiber-reinforced composites generally can be used in high-temperatureapplications. These high-temperature thermosetting resins areundesirable in many applications because they often form brittlecomposites that have relatively low thermal stabilities.

Recently, chemists have sought to synthesize oligomers forhigh-performance, high-temperature advanced composites suitable foraerospace applications. Most formulations for high-temperaturepolymer-matrix composites have monofunctional endcaps which limit thedegree of crosslinking that can be attained. There is a need forhigh-performance composites to exhibit solvent resistance, be tough,impact resistant, strong, and be easy to process. There is also a needfor oligomers and composites that have thermo-oxidative stability, andcan be used at elevated temperatures for extended periods of time.

While epoxy-based composites are suitable for many applications, theyare inadequate for applications which require thermally stable, toughcomposites that are expected to survive for a long time in a hot,oxidizing environment. Recent research has focused on polyimidecomposites to achieve an acceptable balance between thermal stability,solvent resistance, and toughness for these high-performanceapplications. Still the maximum temperatures for use of the polyimidecomposites, such as those formed from PMR-15, can only be used attemperatures below about 600-625° F. (315-330° C.), since they haveglass-transition temperatures of about 690° F. (365° C.). PMR compositesmay be usable in long-term service (50,000 hours) at about 350° F. (170°C.). They can withstand temperatures up to about 600° F. (315° C.) forup to about five hundred hours.

PMR-15 prepregs, however, suffer significant processing limitations thathinder their adoption because the prepreg has a mixture of the unreactedmonomer reactants on the fiber-reinforcing fabric, making them sensitiveto changes in temperature, moisture, and other storage conditions, whichcause the prepregs to be at different stages of cure. Aging these PMRprepregs even in controlled environments can lead to problems. Thereactants on the prepreg are slowed in their reaction by keeping themcold, but the quality of the prepreg depends on its absolute age and onits prior storage and handling history. And, the quality of thecomposite is directly proportional to the quality of the prepregs. Inaddition, for some formulations like PMR-15, the PMR monomers may betoxic or hazardous (especially methylendianiline or MDA in PMR-15),presenting health and safety concerns for the workforce. Achievingcomplete formation of stable imide rings in the PMR composites remainsan issue. These and other problems plague PMR-15 composites.

The commercial long-chain polyimides also present significant processingproblems. AVIMID-N and AVIMID-KIII (trademarks of E. I. duPont deNemours) resins and prepregs differ from PMR-15 because they do notinclude aliphatic chain terminators which PMR-15 uses to controlmolecular weight and to retain solubility of the PMR-15 intermediatesduring consolidation and cure. Lacking the chain terminators, theAVIMIDs can chain-extend to appreciable molecular weights. To achievethese molecular weights, however, the AVIMIDs (and their LaRC cousins)rely on the melting of crystalline powders to retain solubility or, atleast, to permit processing. It has proven difficult to use the AVIMIDsin aerospace parts because of their crystalline melt intermediate stage.

Imides and many other resin backbones have shown surprisingly highglass-transition temperatures, reasonable processing parameters andconstraints for the prepregs, and desirable physical properties for thecomposites by using soluble oligomers having difunctional caps,especially those with nadic caps. Linear oligomers of this type includetwo crosslinking functionalities at each end of the resin chain topromote crosslinking upon curing. Linear oligomers are “monofunctional”when they have one crosslinking functionality at each end. Mostformulations for high-temperature polymer-matrix composites (HTMPCS)have monofunctional endcaps with the exception of chemistries thatcontain dinadic endcaps described in U.S. Pat. No. 5,969,079.

It is known that dinadic- and nadic-endcapped materials react at lowertemperatures than phenylethynyl-endcapped materials, which can limitsome of the chemistries that are possible for HTPMC formulations becausethey will react too rapidly at the point of minimum viscosity, therebyreducing the available processing window for fabricating parts whereliquid-molding processes such as resin transfer molding, resin filminfusion, and vacuum-assisted resin transfer molding are desired.

All currently available phenylethynyl-endcapped materials havemonofunctional endcaps. Thus, the degree of crosslinking is limited. Ithas been shown that difunctional endcaps provide polymers withsignificantly higher mechanical properties than those withmonofunctional endcaps, particularly in aerospace-grade epoxies. Itwould be desirable to provide phenylethynyl-endcapped materials havingthis multi-functionality for use in new, more-processable materialssuitable for high-temperature composites.

BRIEF DESCRIPTION OF THE DISCLOSURE

In one aspect, an oligomer having di-phenylethynyl endcaps is provided.The capped oligomer has the formula:D-A-D

wherein

D is a di-phenylethynyl endcap; and

A is an oligomer selected from the group consisting of imidesulfone;ether; ethersulfone; amide; imide; ester; estersulfone; etherimide;amideimide; oxazole; oxazole sulfone; thiazole; thiazole sulfone;imidazole; and imidazole sulfone.

In another aspect, an advanced composite blend is provided. The advancedcomposite blend includes a di-phenylethynyl capped oligomer having theformula:D-A-D

wherein

D is a di-phenylethynyl endcap; and

A is an oligomer selected from the group consisting of imidesulfone;ether; ethersulfone; amide; imide; ester; estersulfone; etherimide;amideimide; oxazole; oxazole sulfone; thiazole; thiazole sulfone;imidazole; and imidazole sulfone. The composite blend also includes atleast one polymer from a different chemical family than the oligomer.

DETAILED DESCRIPTION OF THE DISCLOSURE

Di-phenylethynyl endcapped oligomers for use in high-temperaturepolymer-matrix composites are disclosed below in detail.Di-phenylethynyl endcaps provide composites with significantly highermechanical properties and increased stability, than knownmono-functional endcaps. Di-phenylethynyl endcaps can have amine,anhydride, hydroxy, or acid chloride functionality to react withbackbones of various different functionalities. For example,amine-functional endcaps can react with anhydride-functional backbones;acid chloride-functional endcaps can react with amine-functionalbackbones; etc. Endcaps can be made from several routes, including, forexample, starting with brominated compounds as bromines that are reactedwith phenylacetylene, using palladium-based catalysts, to replace thebromines with phenylethynyl moieties.

In an exemplary embodiment, blends are used for tailoring the mechanicalproperties of composites while retaining ease of processing. Advancedcomposite blends can be mixed chemical blends of a linear ormulti-dimensional crosslinking oligomer(s) of one chemical family, suchas a heterocycle, and corresponding linear or multidimensionalpolymer(s), unable to crosslink, from a different chemical family, suchas ethersulfone. Generally the polymer has an average formula weightthat is initially higher than that of the oligomer, but the formulaweight of the oligomeric portion of the blend will increase appreciablyduring curing through addition (i.e. homo-) polymerization between thecrosslinking functionalities. The ratio of oligomer(s) to polymer(s) canbe varied to achieve the desired combination of physical properties.Usually the ratio is such that the addition polymer formed during curingconstitutes no more than about 50 mol % of the composite. While twocomponent blends are predominately described below, the blends can bemore complex mixtures of oligomers or polymers with coreactants, ifdesired. The blends may even include coreactive oligomers. By oligomeris meant any molecular weight moiety that includes crosslinkingfunctionalities at its ends to allow it to react to increase theeffective molecular weight when the oligomer cures to form a composite.By polymer is meant any resin that does not include the crosslinkingfunctionalities of the oligomers.

Advanced composite (mixed chemical) blends of the exemplary embodimentinclude a mixture of a crosslinking oligomer from one chemical family,generally selected from the group consisting of, imidesulfone; ether;ethersulfone; amide; imide; ester; estersulfone; etherimide; amideimide;oxazole; oxazole sulfone; thiazole; thiazole sulfone; imidazole; andimidazole sulfone, and a noncrosslinking polymer from a differentchemical family that act as a toughening agent, plasticizer, and thelike. Coreactants may be included in the blends, or they may comprisemixtures of three or more oligomers/polymers. Because the oligomer'saverage formula weight will appreciably increase upon curing, generallythe average formula weight of the polymer in the uncured blend will begreater than that of the oligomer. For example, a linear oligomer mayhave an average formula weight of about 500-5000 while the correspondingpolymer has an average formula weight of about 20,000-40,000. Uponcuring, the oligomer and polymer will generally have average formulaweights that are closer because of addition polymerization of theoligomer. Therefore, the problems sometimes encountered with blendshaving components of widely different average formula weight are not aspronounced in composites formed from the advanced composite blends.

Advanced composite blends allow tailoring of the properties of highperformance composites. They allow averaging of the properties of resinsfrom different families to provide composites that do not have as severeshortcomings as the pure compounds. For example, the rigid nature ofheterocycles (oxazole, thiazole, or imidazole) can be reduced by anadvanced composite blend comprising a heterocycle oligomer and anethersulfone polymer. The resulting composite will have a usetemperature (thermo-oxidative stability) higher than pure ethersulfoneand a flexibility greater than the pure heterocycle. Accordingly, theresulting composites have a blending or averaging of physicalproperties, which makes them candidates for particularly harshconditions.

Suitable oligomer/polymer combinations include, but are not limited to:amideimide/imide; amideimide/imidesulfone; amideimide/heterocycle;amideimide/heterocycle sulfone; imide/heterocycle;imidesulfone/heterocycle; imide/heterocycle sulfone; imide/amide;imidesulfone/amide; ester/amide; estersulfone/amide; ester/imide;ester/imidesulfone; estersulfone/imide; or estersulfone/imidesulfone. Ineach case the oligomer can be either component in the mixture.

Linear oligomers have the general formula:D-A-Dwherein

A=a hydrocarbon residue, from one of the families previously describedabove and having an aromatic, aliphatic, or aromatic and aliphaticbackbone; and

D is selected from the group consisting of:

wherein

-   -   Φ=phenyl    -   R₁=amine, hydroxyl, acid chloride, or anhydride, where R₁ is the        point of attachment to A.

The backbone A in this circumstance, is generally individually selectedfrom the group consisting of: imidesulfones; ethersulfones; amides;ethers; esters; estersulfones; imides; etherimides; amideimides;oxazoles; thiazoles; imidazoles, or heterocycle (i.e. oxazole, thiazoleimidazole) sulfones; and generally include only aromatic (typicallyphenyl) radicals between linkages, although they may have otheraromatic, aliphatic, or aromatic and aliphatic radicals. Although thisdescription will primarily describe para isomers of these backbones,other isomers (particularly meta) can be used. The aromatic radicals inthe backbones may also include nonreactive substituents in some cases,such as aryl, lower alkyl, or lower alkoxy.

Oligomers of the general formula D-A-D are prepared by reacting suitableendcap monomers with the monomer reactants (polymer precursors) that arecommonly used to form the desired backbones.

The di-phenylethynyl endcap monomers can be prepared, in one embodiment,by starting with brominated compounds as bromines, which are reactedwith phenyl acetylene using palladium-based catalysts to replace thebromines with phenylethynyls. For example, the di-phenylethynyl endcapmonomers can be prepared by the following reaction scheme:

The bromine compounds are then reacted with a phenylethynyl acetyleneusing a palladium catalyst:

wherein

-   Φ=phenyl-   R₁=amine, hydroxyl, acid chloride, or anhydride.

In another embodiment, the following reaction scheme can be used.

Suitable palladium catalyst to be used for displacement of a halogenatom from an organic moiety with an acetylinic moiety, include, but arenot limited to: Pd/(PPh₃)₂; PdCl₂/(PPh₃)₂; PdCl₂/CuCl₂/L₁Cl;Pd(OAc)₂/PPh₃/Et₃N; Pd/(PPh₃)₄. Also, palladium-on-carbon (5% Pd/C);(30% Pd/C) or palladium black (pure Pd) can be used. Additionally, PdOor Pd(OAc)₂/benzimidazolium salts can be used. In an exemplaryembodiment, the palladium catalyst, for example, Pd/(PPh₃)₂ orPdCl₂/(PPh₃)₂, is used in the presence of a base, for example,triethyethylamine, a Cu(l) salt, and a solvent, for example, a polarsolvent, for example, tetrahydrofuran.

The acetylene arylation reaction is run in an inert atmosphere atatmospheric pressure at a temperature of 65-85° C. for varying lengthsof time, ranging from 6-48 hours, depending on the particular arylbromide used in the reaction. The time and temperature required isdependent on the nature and position of other substituents on thearomatic nucleus of the aryl bromide.

Triethylamine serves as both a solvent and scavenger for the hydrogenbromide generated during the reaction. Other useful amines which can beused in place of triethylamine are, for example, diethylamine,butylamines, pyridine and the like.

A co-solvent such as toluene, xylene, dimethylformamide, ordimethylacetamide can also be used to improve the solubility of thereactants and/or product. The reaction requires the presence of ahomogenous palladium catalyst which, for example, can be bis(triphenylphosphine) palladium (II) chloride or tetrakis(triphenylphosphine) palladium (O). To improve the utility of thepalladium catalyst, an excess of the phosphine ligand is used. Examplesof such phosphine ligands include: triorthotoluylphosphine andtriphenylphosphine which is preferred because of its availability andcost. The use of palladium complexes to catalyze reactions of this typeis described in the literature, for example, F. R. Heck and H. A. Dieck,J. Organometallic Chem., 93, p. 259-263 (1975). To further facilitatethe reaction a co-catalyst may also be used.

Suitable co-catalysts include cuprous salts, for example, cuprouschloride, cuprous bromide, and cuprous iodide which is preferred. Thereaction is monitored by gas or thin-layer chromatography, monitoringthe disappearance of reactants and/or appearance of product.

The following example which includes the best mode of preparing thecompounds which is representative of the many phenylethynyl compoundswhich are used as end-capping reactants will more fully illustrate theembodiments of this invention.

A multi-necked round-bottom flask fitted with a mechanical stirrer,reflux condenser, and thermometer was flushed and maintained underpositive pressure of nitrogen. The flask was charged with 356 g (1.0mol) of 4,5-dibromo-1,8-naphthalic anhydride, 1 liter of dried, degassedtriethylamine 215.2 g (2.10 mol) of phenylacetylene, 0.80 g (1.01 mmol)of bis-triphenylphosphine palladium II chloride, 3.7 g (14.1 mmol) oftriphenylphosphine, and 0.15 g (0.79 mmol) of cuprous iodide. The systemis brought to mild reflux and maintained at that temperature overnight.

The following morning thin-layer chromatography showed only a tracepresence of the dibromonaphthalic anhydride. The reaction mixture wascooled to room temperature followed by the addition of 350 ml of ether.The. triethylamine hydrobromide byproduct was removed by filtration. Thefiltrate was concentrated on the rotary evaporator, to give thediphenylethynyl derivative of the 1,8-naphthalic anhydride.

Formulations based on the above endcaps can be formed by reacting, forexample, amine functional di-phenylethynyl endcaps with3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA) or2,2′-bis-(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA);orhydroxyl (OH) functional di-phenylethynyl endcaps with4,4′-dichlorodiphenyl sulfone or 4,4′,dichlorodiphenylhexafluoropropane; or acid chloride functional di-phenylethynyl endcapswith 4,4′-methylene dianiline (MDA), 3,4′-oxydianiline (ODA), or1,3-diamino-2,4,5,6-tetrafluorobenzene (DTFBA). Additionally,combinations of different groups within the backbone of the oligomers toimpart different chain stiffness (to increase or decrease stiffness formechanical properties and/or improved processability) may be usedwithout limitation. In one embodiment, molecular weights of theoligomers with di-phenylethynyl endcaps are in the range of about 500 toabout 5000, and in another embodiment, of about 1000 to about 1500 areused.

The synthesis of oligomers and the representative classes of reactantsare presented in greater detail. Amideimides are characterized bybackbones of two general types, namely:

wherein

-   -   R₃=an aromatic, aliphatic, or alicyclic radical, for example, a        phenoxyphenyl sulfone; and    -   R₂=an organic moiety, for example, phenyl or naphthyl.

-   Accordingly, linear polyamideimides include oligomers of the general    formula:

wherein

-   -   Y=a di-phenylethnyl endcap residue as described above;    -   R₂=a trivalent organic radical, for example, phenyl;    -   R₃=an aromatic, aliphatic, or alicyclic radical, for example, a        phenoxyphenyl sulfone.    -   R₄=a divalent organic radical;    -   m=a small integer, usually from 0-5, but generally sufficiently        large to impart thermoplastic properties in the oligomer; and    -   Φ=phenyl.

The amideimides are generally made by condensing suitable endcapmonomers, diacid halides, diamines, and dianhydrides. The dianhydridescan be prepared by condensing 2 moles of an acid halide anhydride of theformula:

wherein R2 is defined above and X is a halogen;with a diamine of the formula: H₂N—R₃—NH₂. The diamine, in this case,can be selected from any of the following diamines. In addition, isomersother than the para diamines shown below may be used, for example 1,3;3,3′; and 3,4.

q=—SO₂—, —S—, —CO—, and —(CF₃)₂C—;

-   Me=methyl; and-   m=a small integer, usually from 0 to 5, but generally sufficiently    large to impart thermoplastic properties in the oligomer.

Other diamines that may be used, including those described in U.S. Pat.Nos. 4,504,632; 4,058,505; 4,576,857; 4,251,417; and 4,215,418, theentire contents of which are incorporated herein by reference for allrelevant and consistent purposes. The aryl or polyaryl “sulfone”diamines previously described can be used, because these diamines aresoluble in conventional synthetic solvents and provide high thermalstability to the resulting oligomers and composites. Diamines mayinclude “Schiff base” conductive linkages (particularly —N═CH—),analogous to diacid halides which will be described.

Ethersulfone (i.e. phenoxyphenyl sulfone) diamines are those in which R¹is

and R″ is

so that the phenoxyphenyl sulfone diamines include:

The molecular weights of these diamines varies from about 500 to about2000. Using lower molecular weight diamines seems to enhance themechanical properties of the difunctional polyamideimide oligomers, eachof which has alternating ether “sulfone” segments in the backbone.

Phenoxyphenyl sulfone diamines of this general nature can be prepared byreacting two moles of aminophenol with (n+1) moles of an aryl radicalhaving terminal, reactive halo-functional groups (dihalogens), such as4,4′-dichlorodiphenylsulfone, and a suitable bisphenol (i.e., dialcohol,dihydric phenol, or diol). The bisphenol is selected from the groupconsisting of:

-   -   2,2-bis-(4-hydroxyphenyl)-propane (i.e., bisphenol-A);    -   bis-(2-hydroxyphenyl)-methane;    -   bis-(4-hydroxyphenyl)-methane;    -   1,1-bis-(4-hydroxyphenyl)-ethane;    -   1,2-bis-(4-hydroxyphenyl)-ethane;    -   1,1-bis-(3-chloro-4-hydroxyphenyl)-ethane;    -   1,1-bis-(3,5-dimethyl-4-hydroxyphenyl)-ethane;    -   2,2-bis-(3-phenyl-4-hydroxyphenyl)-propane;    -   2,2-bis-(4-hydroxynaphthyl)-propane    -   2,2-bis-(4-hydroxyphenyl)-pentane;    -   2,2-bis-(4-hydroxyphenyl)-hexane;    -   bis-(4-hydroxyphenyl)-phenylmethane;    -   bis-(4-hydroxyphenyl)-cyclohexylmethane;    -   1,2-bis-(4-hydroxyphenyl)-1,2-bis-(phenyl)-ethane;    -   2,2-bis-(4-hydroxyphenyl)-1-phenylpropane;    -   bis-(3-nitro-4-hydrophenyl)-methane;    -   bis-(4-hydroxy-2,6-dimethyl-3-methoxyphenyl)-methane;    -   2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane;

-   -   2,2-bis-(3-bromo-4-hydroxyphenyl)-propane; or mixtures thereof        Bisphenols having aromatic character (i.e., absence of aliphatic        segments), such as bisphenol-A, are used in one embodiment.

The dihalogens in this circumstance are selected from the groupconsisting of;

wherein

-   X=halogen; and-   q=—SO₂—, —S—, —CO—, or —(CF₃)₂C—.

The condensation reaction creates ether diamines that ordinarily includeintermediate “sulfone” linkages. The condensation generally occursthrough a phenate mechanism in the presence of K₂CO₃ or another base ina DMSO/toluene solvent. The grain size of the K₂CO₃(s) should fallwithin the 100-250 ANSI mesh range. Additional methods for preparingphenoxyphenysulfones of this general type are disclosed in U.S. Pat.Nos. 3,839,287 and 3,988,374, the entire contents of which areincorporated herein by reference for all relevant and consistentpurposes.

The diacid halide or dicarboxylic acid (i.e. dibasic acid) may includean aromatic chain segment selected from the group consisting of:

-   -   (a) phenyl; (b) naphthyl; (c) biphenyl;    -   (d) a polyaryl “sulfone” divalent radical;    -   (e) a divalent radical illustrated by Schiff base compounds        selected from the group consisting of:

wherein R is selected from the group consisting of: phenyl; biphenyl;naphthyl; or a divalent radical of the general formula:

wherein W=—SO₂—or —CH₂—; and q=0-4; or

-   -   (f) a divalent radical of the general formula:

wherein R¹=a C₂ to C₁₂ divalent aliphatic, alicyclic, or aromaticradical, for example, phenyl.

Thiazole, oxazole, or imidazole linkages, especially between arylgroups, may also be used as the conductive linkages to form theconductive or semiconductive oligomers. The diacid halides include:

Wherein X=halogen.

Schiff base dicarboxylic acids and diacid halides can be prepared by thecondensation of aldehydes and aminobenzoic acid (or other amine acids)in the general reaction scheme:

or similar syntheses.

Polyaryl or aryl diacid halides can achieve the high thermal stabilitiesin the resulting oligomers and composites insofar as aliphatic bonds arenot as thermally stable as aromatic bonds. Particularly, compounds caninclude intermediate electronegative (i.e., “sulfone”) linkages, forexample, —SO₂—, —S—, —CO—, and —(CF₃)₂C— linkages, to improve toughnessof the resulting oligomers.

The corresponding amideimide having the backbone:

can be prepared if the acid anhydride:

is used instead of the acid halide anhydride. The resulting intermediateproducts are dicarboxylic acids rather than dianhydrides. Thesedicarboxylic acids (or their diacid halides) can be used with thediamines previously described.

Dianhydrides useful for the synthesis of amideimides also include:

-   (a) pyromellitic dianhydride,-   (b) benzophenonetetracarboxylic dianhydride (BTDA), and-   (c)    5-(2,5-diketotetrahydrofuryl)-3-methylcyclohexene-1,2-dicarboxylic    anhydride (MCTC), and may be any aromatic or aliphatic dianhydride,    such as those disclosed in U.S. Pat. Nos. 3,933,862; 4,504,632;    4,577,034; 4,197,397; 4,251,417; 4,251,418; or 4,251,420, the entire    contents of which are incorporated herein by reference for all    relevant and consistent purposes. Mixtures of dianhydrides can be    used.

The dianhydrides can also include those intermediates resulting from thecondensation of the acid halide anhydride with any of the diaminespreviously described. Similarly, the dicarboxylic acids and diacidhalides include those intermediates prepared by the condensation of theacid anhydride with any of the diamines previously described. Thecorresponding dicarboxylic acid is converted to the diacid halide (i.e.chloride) in the presence of SOCl₂ (i.e. thionyl chloride).

Amideimides can be synthesized by several schemes, as previouslydescribed. To obtain repeating units of the general formula:

an acid halide anhydride, particularly

can be mixed with a diamine and with an amine functional endcap in theratio of n:n:2 wherein n is an integer greater than or equal to 1. Inthis reaction, the acid halide anhydride will react with the diamine toform an intermediate dianhydride which will condense with the diamineand amine-functional endcap. The reaction may be carried out in twodistinct stages under which the dianhydride is first prepared by mixingsubstantially stoichiometric amounts (or excess diamine) of the acidhalide anhydride and diamine followed by the addition of a mixture ofmore diamine and the endcap. The diamine used to form the dianhydridemay differ from that used in the second stage of the reaction, or it maybe a mixture of diamines from the outset.

The related amideimide having repeating units of the general formula:

can be synthesized by reacting the acid anhydride with the diamine toform intermediate dicarboxylic acids, which can then react with morediamine or an amine-functional endcap to complete the oligomer. Thereaction can be separated into steps.

The amideimide oligomers (as with all oligomers) appear to possessgreater solvent resistance if the condensation of thedianhydride/dicarboxylic acid with the diamine and endcap is donesimultaneously rather than sequentially.

While use of an amine-functional endcap has been described above,corresponding oligomers can be formed by using an acid halide-functionalendcap, if the diamine is provided in excess. In this case the reactionmixture generally comprises the acid halide anhydride or the acidanhydride, the endcap, and the diamine and the synthesis is completedgenerally in one step.

Reactions are typically conducted under an inert atmosphere and atelevated temperatures, if the reaction rate needs to be increased. Thereaction mixture should be well stirred throughout the synthesis.Chilling the reaction mixture can slow the reaction rate and can assistin controlling the oligomeric product.

In one embodiment, the diamine can be in the form of its precursorOCN—R—NCO, if desired. The amideimides described in U.S. Pat. Nos.4,599,383; 3,988,374; 4,628,079; 3,658,938; and 4,574,144, the entirecontents of which are incorporated herein by reference for all relevantand consistent purposes, can be capped with crosslinking monomers toconvert the polymers to oligomers that are suitable for forming advancedcomposite blends.

Polyetherimides and polysulfoneimides are capped to form oligomers thatare suitable for use in the coreactive oligomer blends. Compounds havethe general formula:

wherein

-   X=—O—, or —S—;-   A₁=

-   m=is a small integer, usually 1 to 4;-   Φ=phenyl;-   G=—SO₂—, —S—, —O—, —CH₂—, —CO—, —SO—, C₃F₆, or NHCO;-   R=a trivalent C₍₆₋₁₃₎ aromatic organic radical;-   R₁=amide, imide, or sulfone; and-   R′=a divalent C₍₆₋₃₀₎ aromatic organic radical.

The polyetherimide oligomers can be prepared by several reactionschemes. One such method comprises the simultaneous condensation of:

in the ratio of I:II:III:IV=1:1:m:m+1, wherein m is an integer greaterthan or equal to one, and Y₁=halo- or nitro-. The product has thegeneral formula previously described. The reaction occurs in a suitablesolvent under an inert atmosphere. If necessary, the reaction mixturecan be heated to facilitate the reaction. The reaction conditions aregenerally comparable to those described in U.S. Pat. Nos. 3,847,869 and4,107,147, the entire contents of which are incorporated herein byreference for all relevant and consistent purposes.

Alternatively, the polyetherimides can be prepared by reacting apolyetherimide polymer made by the self-condensation of a phthalimidesalt derivative of the formula:

with crosslinking endcap moieties of the formula:

wherein

X=—O— or —S—;

-   A₁=

-   Φ=phenyl;-   Y₁=halo- or nitro-;-   G=—SO₂—, —S—, —O—, —CH₂, —CO—, —SO—, C₃F₆, or NHCO;-   R₁-amide, imide, or sulfone;-   R′=a divalent C₍₆₋₃₀₎ aromatic organic radical; and-   M=an alkali metal ion or ammonium salt.

The self-condensation proceeds as described in U.S. Pat. No. 4,297,474in a dipolar aprotic solvent. The endcap moieties can be introducedduring the self-condensation to quench the polymerization, or they mightbe added following completion of the polymerization and recovery of thepolyetherimide polymer from methanol. Improved solvent resistance in thecured composites is best achieved, however, by the quenching sequencerather than by the capping sequence which follows polymerization.

Another method for synthesizing polyetherimides involves thesimultaneous condensation of about 2m+2 moles of nitrophthalic anhydridewith about m+1 moles of diamine, about m moles of dialcohol (i.e.,bisphenol, diol, or dihydric phenol), and 2 moles of A₁, having —OHfunctionality, in a suitable solvent under an inert atmosphere. Here,the dialcohol may be in the form of a phenate.

In this reaction, the diamines (which can have aromatic ethersulfonebackbones) react with the anhydride to form intermediates of thefollowing nature in the backbone:

wherein R₂ is a residue of the diamine. Similarly, the dialcohol reactswith the nitro-functionality to form an ether linkage of the generalformula:

wherein R₃ is a residue of the dialcohol. The A₁, having —OHfunctionality, endcaps quench the polymerization. The resultingpolyetherimides have the general formula:

Another synthesis includes the simultaneous condensation of about 2m+2moles of nitrophthalic anhydride with about m+1 moles of dialcohol, mmoles of diamine, and 2 moles A₁, having —NH₂ functionality, in asuitable solvent under an inert atmosphere. Again, the dialcohol may bein the phenate form. The resulting oligomer has a general formula:

Another synthesis includes the simultaneous condensation of 2 m moles ofnitrophthalic anhydride with about m+1 moles of dialcohol, m moles ofdiamine, and 2 moles of A₁, having —NO₂ functionality, in a suitablesolvent under an inert atmosphere. The dialcohol may be in the phenateform or a corresponding sulfhydryl (thio) can be used to form athioether. The resulting oligomer has the general formula:

In any of the syntheses, the dialcohol can be replaced by a comparabledisulfhydryl of the formula: HS—R₂—SH. Mixtures of dialcohols, ordisulfhydryls can be used.

Although the bisphenols previously described can be used, foretherimides, the dialcohol is generally a polyaryl compound andpreferably is selected from the group consisting of:

-   HO—Ar—OH;-   HO—Ar-L-Ar′-L-Ar—OH-   HO—Ar′-L-Ar-L-Ar′—OH    wherein-   L=-CH₂—, —(CH₃)₂C—, —(CF₃)₂C—, —O—, —S—, —SO₂—, or —CO—;

-   T and T₁=lower alkyl, lower alkoxy, aryl, aryloxy, substituted    alkyl, substituted aryl, halogen, or mixtures thereof,-   q=0-4; and-   k=0-3.

The dialcohols also include hydroquinone; bisphenol-A; p,p′-biphenol;4,4′-dihydroxydiphenylsulfide; 4,4′-dihydroxydiphenylether;4,4′-dihydroxydiphenylisopropane;4,4′-dihydroxydiphenylhexafluoropropane; a dialcohol having a Schiffbase segment, the radical being selected from the group consisting of:

wherein R is selected from the group consisting of: phenyl; biphenyl;naphthyl; or a radical of the general formula:

wherein

-   W=—CH₂— or —SO₂—; or a dialcohol selected from the group:

wherein

-   -   L is as previously defined;    -   Me=methyl;    -   m=an integer, generally less than 5, and preferably 0 or 1; and    -   D=any of —CO—, —SO₂—, or —(CF₃)₂C —.

While bisphenol-A is used in the etherimide synthesis, the otherdialcohols can be used to add rigidity to the oligomer withoutsignificantly increasing the average formula weight, and, therefore, canincrease the solvent resistance. Random or block copolymers arepossible.

Furthermore, the dialcohols may also be selected from those described inU.S. Pat. Nos. 4,584,364; 3,262,914; or 4,611,048. Thehydroxy-terminated etherimides of U.S. Pat. No. 4,611,048 can be reactedwith A₁, having —NO₂ functionality, to provide crosslinking etherimidesof the present invention.

Dialcohols of this nature are commercially available. Some may be easilysynthesized by reacting halide intermediates with bis-phenates, such asby the reaction of 4,4′-dichlorodiphenylsulfone with bis(disodiumbiphenolate).

The oligomers can be synthesized in a homogeneous reaction schemewherein all the reactants are mixed at one time (and this scheme ispreferred), or in a stepwise reaction. The diamine and dialcohols can bemixed, for example, followed by addition of the nitrophthalic anhydrideto initiate the polymerization and thereafter the endcaps to quench it.Those skilled in the art will recognize the different methods that mightbe used. To the extent possible, undesirable competitive reactionsshould be minimized by controlling the reaction steps (i.e., addition ofreactants) and the reaction conditions.

Suitable diamines include those diamines described with reference to theamideimide synthesis.

Anhydrides of the formula:

wherein

-   -   X=—O— or —S—;    -   R=a trivalent C₍₆₋₁₃₎ aromatic organic radical;    -   A₁=

-   -   Φ=phenyl;    -   G=—SO₂—, —S—, —O—, —CH₂—, —CO—, —SO—, C₃F₆, or    -   NHCO; and    -   R₁-amine, hydroxyl, acid chloride, or anhydride,        are useful in the synthesis of etherimides, and are prepared by        the condensation of the corresponding endcap phenol or thiol        (—XH) with a nitro- or halo-anhydride that contains the R        moiety.

In at least one synthesis of the etherimides, a compound of the formula:

is an intermediate or reactant, wherein:

-   R=a trivalent C₍₆₋₃₎ aromatic organic radical;-   A₁=

-   Φ=phenyl;-   G=—SO₂—, —O—, —CH₂—, —CO—, —SO—, C₃F₆, or NHCO;-   R₁-amine, hydroxyl, acid chloride, or anhydride;-   Y₁=halo or nitro.

This intermediate is formed by reacting A₁, having —NH₂ functionality,with a substituted phthalic anhydride of the formula:

These substituted anhydrides are described in U.S. Pat. Nos. 4,297,474and 3,847,869, the entire contents of which are incorporated herein byreference for all relevant and consistent purposes.

Polysulfoneimide oligomers corresponding to the etherimides can beprepared by reacting about m+1 moles of a dianhydride with about m molesof a diamine and about 2 moles of an amine functional endcap (A₁—NH₂).The resulting oligomer has the general formula:

wherein R and R′ are divalent aromatic organic radicals having from 6-20carbon atoms. R and R′ may include halogenated aromatic C₍₆₋₂₀₎hydrocarbon derivatives; alkylene radicals and cycloalkylene radicalshaving from 2-20 carbon atoms; C₍₂₋₈₎ alkylene terminatedpolydiorganosiloxanes; and radicals of the formula:

wherein

-   q=—C_(y)H_(2y)—, —CO—; —SO₂—, —O —, —S—, —SiXX′—, or    —SiXX′—O—SiXX′—;-   y=1 to 5; and-   XX′=aliphatic, aromatic, or hydrogen.

Although the concept of advanced composite blends is probably bestsuited to linear morphology, the advanced composite blends of thepresent invention also include multidimensional oligomers and polymers.A multidimensional oligomer includes an aromatic hub and three or moreradiating chains or arms, each chain terminating with a crosslinking endcap segment. Each chain includes the resin linkages previouslydescribed. Each chain is substantially the same. For example, amultidimensional ether can be prepared by the simultaneous condensationof phloroglucinol with a dihalogen and an end cap monomer.

In multidimensional oligomers the higher density of crosslinkingfunctionalities in a multidimensional array provides increasedthermo-oxidative stability to the cured composites. Usually the hub willhave three radiating chains to form a “Y” pattern. In some cases, fourchains may be used. Including more chains leads to steric hindrance asthe hub is too small to accommodate the radiating chains. Atrisubstituted phenyl hub is highly preferred with the chains beingsymmetrically placed about the hub. Biphenyl, naphthyl, azaline (e.g.,melamine), or other aromatic moieties may also be used as the hubradical.

Multidimensional polyamideimide oligomers include oligomers of thegeneral formula:

wherein Y, R2, R3, R4, and m are as previously defined with respect tothe linear amideimides, Ar=an organic radical of valency w; .Φ=phenyl,and w=3 or 4. Preferably, Ar is an aromatic radical (generally phenyl)generally selected from phenyl, naphthyl, biphenyl, azalinyl (such asmelamine), or triazine derivatives of the general formula:

wherein R₂=a divalent hydrocarbon residue containing 1-12 carbon atoms,as described in U.S. Pat. No. 4,574,154.

The hub may also be a residue of an etheranhydride of the formula:

or an etheramine of the formula:Ar—[—O—φ—NH₂]_(w)

The best results are likely to occur when the arm length of theoligomers is as short as possible (to allow ease of processing) and theoligomer has six crosslinking sites (to allow the highest density ofcrosslinking). In one embodiment, the hub includes the phenyl radical,since these compounds are relatively inexpensive, are more readilyobtained, and provide oligomers with high thermal stability.

The chains of the oligomers include crosslinking end caps which improvethe solvent-resistance of the cured composites. These end caps may bethermally or chemically activated during the curing step to provide astrongly crosslinked, complex, multi-dimensional array of interconnectedoligomers.

The oligomers may be formed by the attachment of arms to the hubfollowed by chain extension and chain termination. For example,trihydroxybenzene may be mixed with p-aminophenol and4,4′-dibromodiphenylsulfone and reacted under an inert atmosphere at anelevated temperature to achieve an amino-terminated “star” of thegeneral formula:

that can be reacted with suitable diacid halides, diamines, and end capsto yield a polyamideimide oligomer.

The etheranhydride hub can be synthesized by reacting nitrophthalicanhydride or halophthalic anhydride with Ar(—OH)w in a suitable solventunder an inert atmosphere, as described generally in U.S. Pat. Nos.3,933,862 and 4,851,495 (thio-analogs).

The oligomers of course, might be made by reacting nitrophthalicanhydride with an amine functional end cap followed by the condensationwith the hydroxy hub or in similar reaction schemes that will beunderstood by those of ordinary skill.

The oligomers can be synthesized in a homogeneous reaction schemewherein all the reactants are mixed at one time, or in a stepwisereaction scheme wherein the radiating chains are affixed to the hub andthe product of the first reaction is subsequently reacted with the endcap groups. Of course, the hub may be reacted with end-capped arms thatinclude one reactive, terminal functionality for linking the arm to thehub. Homogeneous reaction is preferred, resulting undoubtedly in amixture of oligomers because of the complexity of the reactions. Theproducts of the processes (even without distillation or isolation ofindividual species) are oligomer mixtures which can be used withoutfurther separation to form desired advanced composites.

Linear or multidimensional oligomers can be synthesized from a mixtureof four or more reactants so that extended chains may be formed. Addingcomponents, however, adds to the complexity of the reaction and of itscontrol. Undesirable competitive reactions may result or complexmixtures of macromolecules having widely different properties may beformed, because the chain extenders and chain terminators are mixed, andcompete with one another.

Multidimensional etherimides can be made by reacting the etheranhydridehub with compounds of the formulae II, III, and IV previously described.

Multidimensional amides are prepared by condensing a nitro, amine, oracid halide hub with suitable diamines, dicarboxylic acid halides, andamine or acid halide end cap monomers to form oligomers of the generalformulae:AR—[—CONH—P—NHCO-Q-CONH-φ-D_(i)]_(w);Ar—[—NHCO-Q-CONH—P—NHCO-φ-D_(i)]_(w);Ar—[—CONH-φ-D_(i)]_(w);Ar—[—NHCO-φ-D_(i)]_(w);Ar—[—CONH—P—NHCO-φ-D_(i)]_(w);orAr—[—NHCO-Q-CONH-φ-D_(i)]_(w),wherein Ar, w, -Φ-, i, and D are as previously defined, P=a residue of adiamine, and Q=a residue a dicarboxylic acid halide.

Multidimensional imides can be made using the amine, etheranhydride, oretheramine hubs with suitable dianhydrides, and amine or anhydride endcaps. Particularly preferred multidimensional imides include bycondensing anhydride end caps directly with the amine hubs.

Multidimensional polyesters can be made using hydroxy or carboxylic acidhubs (particularly cyuranic acid) with suitable diols and diacidhalides. Carboxylic acid hubs include those compounds described in U.S.Pat. No. 4,617,390 and compounds prepared by reacting polyols, such asphloroglucinol, with nitrobenzoic acid or nitrophthalic acid to formether linkages and active, terminal carboxylic acid funtionalities. Thenitrobenzoic acid products would have three active sites while thenitrophthalic acid products would have six; each having the respectiveformula:φ-[-O-φ-COOH]₃orφ-[-O-φ-(COOH)₂]₃wherein Φ=phenyl. Of course other nitro/acids can be used.

Hubs can also be formed by reacting the corresponding halo-hub (such atribromobenzene) with aminophenol to form triamine compounds representedby the formula:

which can then be reacted with an acid anhydride to form apolycarboxylic acid of the formula:

wherein Φ=phenyl; the hub being characterized by an intermediate etherand imide linkage connecting aromatic groups. Thio-analogs are alsocontemplated, in accordance with U.S. Pat. No. 3,933,862.

The hub may also be a polyol such as those described in U.S. Pat. No.4,709,008 to tris(hydroxyphenyl)alkanes of the general formula:

wherein R=hydrogen or methyl and can be the same or different. Thepolyols are made by reacting, for example, 4-hydroxybenzaldehyde or4-hydroxyacetophenone with an excess of phenol under acid conditions (asdisclosed in U.S. Pat. Nos. 4,709,008; 3,579,542; and 4,394,469).

The polyols may also be reacted with nitrophthalic anhydride,nitroaniline, nitrophenol, or nitrobenzoic acids to form other compoundssuitable as hubs as will be understood by those of ordinary skill.

Phenoxyphenyl sulfone arms radiating from a hub with a terminal amine,carboxylic acid, or hydroxyl group are also precursors for makingmultidimensional polyester oligomers of the present invention.

The best results are likely to occur when the hub is phloroglucinol orcyuranic acid. In either case a suitable end-cap monomer (phenol or acidhalide) can be reacted with the hub to form “short-armed,”multidimensional oligomers having three or six crosslinking sites. Thesecompounds are the simplest multidimensional oligomers and are relativelyinexpensive to synthesize.

Multidimensional amides, amide imides, heterocycles, and heterocyclesulfones can be prepared using these carboxylic acid hubs, as will beunderstood by those of ordinary skill in the art.

Multidimensional oligomers of the formula:

can also be synthesized with an Ullmann aromatic ether synthesisfollowed by a Friedel-Crafts reaction. Wherein, Q=

q=—SO₂—, —CO—, —S—, or —(CF₃)₂C—, and preferably —SO₂—, or —CO—; and

-   -   Y₁=a crosslinking end cap as previously defined (i.e. D_(i)-Φ-).

To form the Ar—O-Φ-CO—Y₁]_(w) oligomers, a halosubstituted hub isreacted with phenol in DMAC with a base (NaOH) over a Cu Ullmanncatalyst to produce an ether “star” with active hydrogens para- to theether linkages. For example, 1 mole of trichlorobenzene can be reactedwith about 3 moles of phenol in the Ullmann ether reaction to yield anintermediate of the general formula: Φ-(-O-Φ)₃, which can be reactedwith about 3 moles of (Y₁)—COCl to produce the final, crosslinkable,ether/carbonyl oligomer.

Blends can improve impact resistance of pure oligomer composites withoutcausing a significant loss of solvent resistance. The advanced composite(i.e. mixed chemical) blends of the present invention comprise mixturesof one or more crosslinkable oligomer and one or more polymer from adifferent chemical family. The polymers are incapable of crosslinking.The crosslinkable oligomer and the compatible polymer can be blendedtogether by mixing mutually soluble solutions of each. While the blendis often equimolar in the oligomer and polymer, the ratio of theoligomer and polymer can be adjusted to achieve the desired physicalproperties. The properties of the composite formed from the advancedcomposite blend can be adjusted by altering the ratio of formula weightsfor the polymer and oligomer.

In synthesizing the polymers, quenching compounds can be employed, ifdesired, to regulate the polymerization of the comparable polymer, sothat, especially for linear systems, the polymer has an average formulaweight initially substantially greater than the crosslinkable oligomer.For thermal stability, an aromatic quenching compound, such as aniline,phenol, or benzoic acid chloride is preferred. The noncrosslinkingpolymer can be made by the same synthetic method as the oligomer withthe substitution of a quenching cap for the crosslinking end cap.

While the best advanced composite blends are probably those of modestformula weight and those in which the oligomer and polymer are inequimolar proportions, other compositions may be prepared, as will berecognized by those of ordinary skill in the art.

Solvent resistance of the cured composite may decrease markedly if thepolymer is provided in large excess to the oligomer in the blend.

The advanced composite blends may, in the case of coreactive oligomersand in other cases, include multiple oligomers or multiple polymers,such as a mixture of an amideimide oligomer, an amide oligomer, and animide polymer or a mixture of an amideimide oligomer, an amideimidepolymer, and an imide polymer (i.e. blended amideimide further blendedwith imide). When polyimide oligomers are used, the advanced compositeblend can include a coreactant, such as p-phenylenediamine, benzidine,or 4,4′-methylene-dianiline. Ethersulfone oligomers can include theseimide coreactants or anhydride or anhydride-derivative coreactants, asdescribed in U.S. Pat. No. 4,414,269. Other combinations of oligomers,polymers, and coreactants can be used, as will be recognized by those ofordinary skill in the art.

As discussed above, the oligomeric component of the advanced compositeblend may itself be a blend of the oligomer and a compatible polymerfrom the same chemical family, further blended with the compatiblepolymer from the different family. The advanced composite blends, also,can simply be made from three or more oligomeric or polymericcomponents. They generally include only one oligomeric component unlesscoreactive oligomers are used.

HYPOTHETICAL EXAMPLES

1. Synthesis of Compound (a) from Above:

A diamine of the formula H₂N—R₃—NH₂ is reacted with two moles of an acidanhydride of the formula:

to form a dicarboxlic acid intermediate of the formula:

The intermediate is converted to the corresponding diacid chloride inthe presence of SOCl₂, which is then condensed with one mole of adiamine of the formula H2N—R4-NH₂ and two moles of an amine endcap ofthe formula Y-Φ-NH₂ to yield the desired product.

If excess diamine of the formula H₂N—R₄—NH₂ is used along with an acidhalide endcap of the formula Y-Φ-COX, the product can have the formula:

2. Synthesis of compound (b) from Above:

A diamine of the formula H₂N—R₃—NH₂ is reacted with

to yield a dianhydride intermediate of the formula:

The intermediate is then condensed with Y-Φ-COCl and a diamine of theformula H₂N—R₄—NH₂ to yield the desired product.3. Synthesis of Compound (d) from Above:

A diamine of the formula H₂N—R₃—NH₂ is reacted with an acid anhydride asin Example 1 to form a dicarboxylic acid intermediate that can bereacted with another diamine of the formula H₂N—R₄—NH₂ and an acidhalide endcap of the formula Y-Φ-COCl to yield the desired product.

4. Synthesis of Amideimide Having One Diamine

Two moles of an amine endcap are reacted with about (m+2) moles of anacid anhydride, such as phthalyl acid anhydride, and about (2m+1) molesof a diamine, such as H₂N-Φ-SO₂₋Φ-O-Φ-SO₂—NH₂, to yield the desiredproduct. To avoid side or competitive reactions, it is probablydesirable to prepare a dicarboxylic acid intermediate of the formula:

by mixing the acid anhydride and diamine in the ratio of about 2 molesacid anhydride: 1 mole diamine prior to adding the remaining reactantsfor simultaneous condensation to the oligomer.5. Preparation of an Advanced Composite Blend

The polyamideimide oligomer of Example 1, wherein R₂═R₃═R₄=phenyl, m=1,i=2, and Y=

is dissolved in a suitable solvent.

A relatively high-average-formula weight polyether polymer is made bycondensing a dialcohol of the general formula.HO-φ-O-φ-O-φ-O-φ-OHwith Cl-Φ-Cl and phenol (to quench the polymerization) under an inertatmosphere in the same solvent as used with the polyamideimide oranother solvent miscible with that of the polyamideimide.

The two solutions are mixed to form the advanced composite blend, whichcan be prepregged or dried prior to curing to an advancedamideimide/ether composite.

6. Synthesis of a Multidimensional Polyamide.

The oligomer is prepared by reacting:

under an inert atmosphere to yield:

7. Synthesis of a Difunctional, Multidimensional Polyamide. TheObligomer is Prepared by Reacting:

under an inert atmosphere to yield:

Competitive side reactions between the reactants in Example 7 willlikely hinder the yield of this product and will make isolation of theproduct difficult. Yield can be enhanced by adding the reactantsserially, but the physical properties of the resulting oligomers mightbe impaired.8. Synthesis Using an Etheramine Hub:

Another multidimensional oligomer is prepared by reacting:

Under an inert atmosphere to yield:

While the disclosure has been described in terms of various specificembodiments, those skilled in the art will recognize that the inventioncan be practiced with modification within the spirit and scope of theclaims.

1. An oligomer having di-phenylethenyl endcaps comprising the formula:D-A-D wherein D is a di-phenylethynyl endcap of

wherein Φ=phenyl; G =—SO₂—, —S—, —O—, —CH₂—, —CO—, —SO—, C₃F₆, or NHCO;and R₁=amine, hydroxyl, acid chloride, or anhydride, where R1 is thepoint of attachment to A; and A is an oligomer selected from the groupconsisting of imidesulfone; ether; ethersulfone; amide; imide; ester;estersulfone; etherimide; amideimide; oxazole; oxazole sulfone;thiazole; thiazole sulfone; imidazole; and imidazole sulfone.
 2. Anoligomer having di-phenylethenyl endcaps in accordance with claim 1wherein A is an amideimide, the amideimide comprising repeating units ofthe formula:

wherein R₃=an aromatic, aliphatic, or alicyclic radical; and R₂=anorganic moiety.
 3. An oligomer having di-phenylethynyl endcaps inaccordance with claim 1 wherein A is a polyetherimide orpolysulfoneimide, and the oligomer has the formula:

wherein X=—O—, or —S—; A₁=

m=1 or 2; Φ=phenyl; R=a trivalent C₍₆₋₁₃₎ aromatic organic radical;R₁=amide, imide, or sulfone; G=—SO₂—,—S—,—O—,—CH₂—,—CO—,—SO—, C₃F₆, orNHCO; and R¹=a divalent C₍₆₋₃₀₎ aromatic organic radical.
 4. An oligomerhaving di-phenylethynyl endcaps in accordance with claim 1 wherein A isan aromatic or aromatic/aliphatic imide residue that includes at leastone segment of the formula:Φ-O-Φ-SO₂-Φ-O-Φ-.
 5. An oligomer having di-phenylethynyl endcaps inaccordance with claim 4 wherein A is an alternating imide made from thecondensation of a dianhydride and a diamine.
 6. An oligomer havingdi-phenylethynyl endcaps in accordance with claim 5 wherein A isaromatic.
 7. An oligomer having di-phenylethynyl endcaps in accordancewith claim 1 wherein A is an imide made by condensing a dianhydridemonomer and a diamine monomer, said dianhydride is:

and said diamine is

or a mixture thereof.
 8. An advanced composite blend comprising adi-phenylethynyl capped oligomer having the formula:D-A-D wherein D is a di-phenylethynyl endcap of

wherein Φ=phenyl; G =—SO₂—, —S—, —O—, —CH₂—, —CO—, —SO—, C₃F₆, or NHCO;and R₁=amine, hydroxyl, acid chloride, or anhydride, where R1 is thepoint of attachment to A; and A is an oligomer selected from the groupconsisting of imidesulfone; ether; ethersulfone; amide; imide; ester;estersulfone; etherimide; amideimide; oxazole; oxazole sulfone;thiazole; thiazole sulfone; imidazole; and imidazole sulfone; and atleast one compatible polymer from a different chemical family than theoligomer, the one compatible polymer is selected from the groupconsisting of imidesulfone; ether; ethersulfone; amide; imide; ester;estersulfone; etherimide; amideimide; oxazole; oxazole sulfone;thiazole; thiazole sulfone; imidazole; and imidazole sulfone.
 9. Anadvanced composite blend in accordance with claim 8 wherein A is anamideimide, the amideimide comprising repeating units of the formula:

wherein R₃=an aromatic, aliphatic, or alicyclic radical; and R₂=anorganic moiety.
 10. An advanced composite blend in accordance with claim8 wherein A is a polyetherimide or polysulfoneimide, and the oligomerhas the formula:

wherein X=—O—, or —S—; A₁=

m=1 to 4; Φ=phenyl; R=a trivalent C₍₆₋₁₃₎ aromatic organic radical;R₁=amide, imide, or sulfone; G=—SO₂—,—S—, —O—,—CH₂—,—C—,—SO—, C₃F₆, orNHCO; and R′=a divalent C₍₆₋₃₀₎ aromatic organic radical.
 11. Anadvanced composite blend in accordance with claim 8 wherein A is anaromatic or aromatic/aliphatic imide residue that includes at least onesegment of the formula:Φ-O-Φ-SO₂-Φ-O-Φ-.
 12. An advanced composite blend in accordance withclaim 11 wherein A is an alternating imide made from the condensation ofa dianhydride and a diamine.
 13. An advanced composite blend inaccordance with claim 11 wherein A is aromatic.
 14. An advancedcomposite blend in accordance with claim 8 wherein A is an imide made bycondensing a dianhydride monomer and a diamine monomer, said dianhydrideis:

and said diamine is

or a mixture thereof.